Silos for cereal grain and the like are evacuated by means of allowing the grain to flow out through an outlet in the bottom of the silo. In order to be able to utilize the volume of the silo to the greatest possible extent, the silo bottom is conveniently arranged in a horizontal direction, resulting in the formation of a remaining residue of bulk goods, corresponding to the angle of repose of the material in question, which has its largest height at the silo walls and slopes towards the outlet or the outlets. Thereby, it is desired that this remaining material is evacuated by means of an evacuation conveyor, which consists of a floor having a number of bands of perforations, through which perforations jets of pressurized air directed along the floor pass, and bring the bulk goods into movement towards an outlet opening or the like. SE 218067 C and SE 459 575 B are examples of previously known devices of this type.
A disadvantage with these previously known devices is that the pressurized air locates passages in which the lowest resistance prevail, i.e. where the layer of bulk goods is the thinnest, thereby leaving the thicker portions more or less unaffected. In the positions where the pressurized air has been able to transport away the goods, empty or sparsely coated floor areas are created, and a considerable portion of the pressurized air flows out from the silo without having been effective in the displacement of the cereal grain.